The invention relates to a method for driving an electronic metering system with an electrical hand metering device and to a metering system for carrying out the method.
Electronic metering devices are applied in the laboratory for metering fluids. They are known in various embodiments. Metering devices functioning according to the air cushion principle have an integrated piston-cylinder unit, by way of which an air column is displaceable in order to suction sample fluid into a metering syringe and to expel this from the syringe. With this the piston-cylinder unit does not come into contact with the fluid. Only the metering syringe which as a rule consists of plastic is contaminated and may be exchanged after use.
With direct displacement metering devices on the other hand a syringe is directly filled with sample fluid. The piston and the cylinder of the syringe are thus contaminated by the fluid so that the syringe before the exchange of the fluid mostly must be replaced by a new syringe or be cleaned. Also this syringe consists as a rule of plastic.
Pistonless metering devices may comprise a metering tip with a balloon-like end section which is expanded for suctioning fluid, and for expulsion is compressed. Such metering tips are also already conceived as an exchange part.
Micro-metering devices may have a micro-membrane pump and/or a free jet metered, wherein at least one of these components is designed with micro-system technology, in particularly with silicon, glass and plastic injection molding technology and/or plastic imprinting technology. The metering is achieved by deformation of a wall of a container which is filled with fluid. The electrical drive for the deformation of the wall may be piezoelectric, thermoelectric, electromagnetic, electrostatic, electromechanical, magnetorestrictive, etc.
Air cushion, direct displacement, pistonless and micro-metering devices may have an unchangeable or changeable metering volume. A changing of the metering volume is achieved by adjustment of the displacement of the displacement means, i.e. of the displacement path of the piston or of the degree of deformation of the balloon-like end section or of the chamber wall.
Dispensers are metering devices which may repetitively dispense an accommodated fluid in small part quantities.
Furthermore there are multi-channel metering devices which have several xe2x80x9cchannelsxe2x80x9d by way of which it is simultaneously metered.
All metering devices may be designed as hand apparatus.
All previously mentioned metering devices may be electronic metering devices in the meaning of this application. With this they comprise a drive means with an electrical drive for driving a displacement means. Furthermore they have an electronic control and/or regulating means in particular for the drive, which may be an electrical drive motor, an electric linear drive or a drive mentioned in the context of micro-metering devices. Furthermore they have an electrical voltage source for supplying the control and/or regulating means and a drive, which may be chargeable. Electronic metering devices have the advantage of the high reproducibility of meterings. In particular by way of preset metering speeds (xcexcl/s) more exact results may be achieved than with manually driven apparatus. Furthermore they may have the advantage of the multi-functionality, since they may carry out functions of pipetting, dispensing, titrating, mixing, etc.
The known electronic hand metering devices Response(copyright) of the applicant function according to the air cushion principle and are obtainable in the single-channel or multi-channel design. Four models cover the metering range of 0.5 xcexcl to 5 ml. This metering device may function in various operating manners, amongst other things pipetting and dispensing. The dispensing is possible in up to 25 part steps. The user may select between three various metering speeds. The metering device may be applied for charging the accumulator cells in a charging station.
From EP 0 864 364 A2 there is known a similar hand metering device with chargeable batteries and a charging station for their charging. The hand metering device may be operated in various operating modes, which apart from pipetting and dispensing have a free hand operation. Therein the hand metering device is programmed such that it controls the suctioning, the dispensing and time delays for exchanging and treating the metering tip. It carries out these program steps via a predetermined number of cycles.
The previously known electronic hand metering devices have the disadvantage that the specific operating parameters (e.g. step widths of the piston advance, metering speeds, charging condition criteria, display outputs) and the program are fixedly predetermined. The electronic control means specifically comprises a computer which functions according to a fixed stored program in which these parameters are contained. Thus for each model a special software is required and a retrospective change of the parameters is hardly possible. Furthermore it is disadvantageous that the programming of the free hand operation must be effected tediously via the keyboard of the hand metering device and that in the free hand operation the steps which are programmed in must be rigidly worked through and the course of operation may not be influenced.
Metering devices are testing means within the sense of GLP (Good Laboratory Practice) guidelines and comparable QS standards (ISO 9000 ff, EN 45000 ff).
According to the GLP guidelines the error limits published by the manufacturer must be checked at regular time intervals. By way of the applicant there is known a system with which the calibration of metering devices may be carried out quickly, comfortably and inexpensively.
This system is based on a calibration software PICASO(copyright) which runs on a PC. Furthermore one requires a measuring construction which comprises weighing vessels, adapters carrying sleeves as well as vapor traps and a semi-microscale. In the software there is laid down all relevant data for the metering devices to be tested. Deviations from these nominal values after transferring the weighing values to the computer are immediately evaluated. A measuring row has up to 15 individual weighings. From these the mean value, incorrectness, impression and standard deviation are evaluated and compared to predetermined nominal values. All measuring and reference data may be protocolled according to GLP-DIN.
With the calibration via the operating keyboard of the electronic hand metering pipette the metering data is inputted and their operation controlled. The weighing values are typed into a PC. This is tedious and may lead to errors.
The object of the invention is to provide a method for operating an electronic metering system with improved operating parameters, operating procedures, program parts or complete programs. Another object of the present invention is to provide a metering system. A method solving the object is specified in claim 1. Formations of this as well as advantageous metering systems for carrying it out is the subject matter of the subsequent claims.
This object is achieved by a method for operating an electronic metering system with an electronic hand metering device. The hand metering device comprises a drive means comprising an electrical drive; at least one displacement means drivable by the drive means, for metering the fluid; a program-controlled electronic control and/or regulating means, in particular for the drive; at least one non-volatile write-read memory; an electrical voltage source in particular for the electrical drive and the electronic control and/or regulating means and a data interface. The data interface is connected to the electronic control and/or regulating means, with a computer and with a data transfer means. The data transfer means comprises a data interface for connecting the data interface of the metering device to the computer, wherein the parameters specific to at least one of the apparatus type, the apparatus, user parameters, routines for carrying out operating procedures, the program, at least one programming part may be written into and read from the write-read memory and the hand metering device can be remotely controlled by the computer via the data interfaces.
According to the invention thus by way of the external computer access may be made to the write-read memory of the hand metering device. This opens the possibility of changing the operating parameters which the program-controlled electronic control and/or regulating means falls back on for carrying out the operating procedures.
These may be parameters specific to the apparatus type, in particular those which are predetermined for carrying out operating procedures. For example these could be parameters determining the movement of the piston of a displacement means (e.g. acceleration characteristics, piston speed, drive force, retaining moment). Furthermore these may be quantity-determining parameters (e.g. basic values and limit values of metering quantities, possible numbers of metering steps, overstroke volume for the expulsion of remaining fluid). Other parameters specific to the apparatus may in particular concern the monitoring of operating conditions, (e.g. evaluation criteria for the charged condition of an accumulator, for the actuation of the end switch or for the duration of the idle pause for the purpose of switching to a xe2x80x9csleep conditionxe2x80x9d). Parameters specific to the apparatus may in particular be an identification of the apparatus, a recognition code for a respective stored parameter set, etc.
User parameters are data which also manually may be inputted by the user via a keyboard of the hand metering device. To this belong in particular the metering volume, metering speeds etc. Further use parameters concern the calibration of the hand metering device. In a simple case it may be the case of a correction factor for converting the set metering quantities to the actually dispensed metering quantities. This may in particular also be coefficients of a function which contains the deviation of the set metering quantities from the actually dispensed metering quantities given varying quantity settings.
Furthermore the invention opens the possibility by way of the external computer of placing routines for carrying out operating procedures in the write-read memory of the hand metering device so that the program-controlled electronic control and/or regulating means falls back on these. These routines may be set up by the user and serve the control of operating courses made up of several operating procedures, in particular if these are to be repeatedly gone over. For example by way of such a xe2x80x9cshort programxe2x80x9d the accommodation, mixing and dispensing of certain fluid quantities may be controlled or a thinning row with which the dispensed metering volume is to be halved from thinning step to thinning step. With this the use of routines is simplified for the user. There also exists the possibility of recording routines stored in the computer into the hand metering device.
Furthermore by way of the external computer the program of the program-controlled electronic control and/or regulating means or at least a part of this may be written into the write-read memory and/or read out from this. For this the memory is preferably a flash memory of a processor. A processor with a flash memory has implemented a program presupposed by the manufacturer which for a data exchange may initiate the communication. By way of this it is possible to play into each hand metering device a partly or completely different program from the outside via the data interfaces or to completely or partly change the program.
Furthermore by way of the external computer a remote control of the hand metering device is possible. This in particular favors the calibration in that the respective metering data by way of the computer is transmitted to the hand metering device and where appropriate even its operation is completely controlled by way of the computer. Furthermore the computer may protocol the respective metering data. Where appropriate this may be effected together with the respective readings if these are acquired and played into the computer. Furthermore by way of the computer a wire-connected or wireless remote control of the hand metering device may be effected. This in particular favors an automation of the metering procedures, the application of the hand metering device in a higher-order automisation process or a safe metering in contaminated surroundings.
Thus the invention permits the fixing of specific parameters of the metering device only after the apparatus assembly, even if this includes the installation of a building block with fixed programmed-in software. By way of this it becomes possible for various apparatus models to use one and the same software and electronics hardware. The respective parameters may be fixed according to requirements or even changed. In the extension of this concept even a fixing or change, specific to apparatus type and to apparatus, of program parts or of the whole program is possible. By way of the ability to store user parameters by way of an external computer an additional advantageous operating possibility is created. The invention also favors the automisation of the calibration and of the end control in the manufacture. A simple update to new operating parameters is made possible for the service. The OEM customer may in turn carry out a parameterization for special OEM metering parts. The GLP parameter documentation is made simple for the user and a simplified calibration with PC software is made possible. Also the incorporation into automisation processes is simplified for the user and a remote control is made possible.
The data interfaces of the hand metering device and the data transfer means may be connected to one another for a duration or permanently. It may be the case of data interfaces which are only connected to one another when the hand metering device is applied into the data transfer means. The data interfaces may however also be connected to one another independently of whether the hand metering device is applied into the data transfer means.
The data interfaces of the hand metering device and the data transfer means may be connected by radio transmitters and radio receivers communicating with one another. Also the data interfaces may comprise IR transmitters and IR receivers communicating with one another. By way of this a permanent connection of the data interfaces or a wireless remote control is favored. Additionally or instead of this the data interfaces may comprise electrical contacts able to be connected to one another, which may be connectable by way of application of the hand metering device into the data transfer means.
Preferably the electronic control means comprises a microcomputer, in particular a micro-controller. The data transfer means may be connected to a separate computer for example to a PC or to an integrated computer, in particular a microcomputer or micro-controller.
The electronic control and/or regulating means and/or the computer may comprise usual input and output and memory means, including an exchangeable memory medium. On the exchangeable memory medium there may be present a program for the remote control and/or the calibration of the hand metering device. This favors the equipping of the metering system with software according to requirements and its actualization.
The hand metering device may operate independently of the mains electricity. In particular it may be provided with a chargeable voltage source, for example one or more accumulators. For this case it may have an interface connected to the chargeable voltage source and the data transfer means may comprise a charging part for charging the voltage source and a charging interface connected to the charging part, for connecting to the charging interface of the hand metering device. The charging interfaces of the hand metering device and the data transfer means may have cooperating electrical charging contacts. These may coincide with the contacts of the data interfaces. The data transmission may in particular be effected with the charging voltage or the charging current of the charging part By modulation of the charging voltage of the charging current on the same physical channel a data transmission may be realized.
The data transfer means may be designed as a stationary part. In particular in this case the hand metering device may also be used as a stationary apparatus or as a metering automatic machine when it is applied into the data transfer means. Then the voltage supply of the hand metering device may be ensured via the charging part.
Further formations of the invention are specified in the dependent claims.